Vessel sealer and divider for use with small trocars and cannulas

ABSTRACT

An endoscopic bipolar forceps includes a housing and a shaft affixed to the housing. The shaft includes a longitudinal axis defined therethrough and a pair of jaw members attached to a distal end thereof. The forceps also includes a drive assembly for moving one of the jaw members relative to the other jaw member from a first position wherein the movable jaw members are disposed in spaced relation relative to each other to a second position wherein the jaw members are closer one another for manipulating tissue. A movable handle is included which is rotatable about a pivot to force a drive flange of the movable handle into mechanical cooperation with the drive assembly to move the jaw members from the open and closed positions. The pivot is located a fixed distance from the longitudinal axis and the drive flange is located generally along the longitudinal axis. The forceps is connected to a source of electrosurgical energy connected to each jaw member such that the jaw members are capable of conducting bipolar energy through tissue held therebetween to effect a tissue seal.

BACKGROUND

[0001] The present disclosure relates to an electrosurgical forceps andmore particularly, the present disclosure relates to an endoscopicbipolar electrosurgical forceps for sealing and/or cutting tissue.

TECHNICAL FIELD

[0002] Electrosurgical forceps utilize both mechanical clamping actionand electrical energy to effect hemostasis by heating the tissue andblood vessels to coagulate, cauterize and/or seal tissue. As analternative to open forceps for use with open surgical procedures, manymodern surgeons use endoscopes and endoscopic instruments for remotelyaccessing organs through smaller, puncture-like incisions. As a directresult thereof, patients tend to benefit from less scarring and reducedhealing time.

[0003] Endoscopic instruments are inserted into the patient through acannula, or port, which has been made with a trocar. Typical sizes forcannulas range from three millimeters to twelve millimeters. Smallercannulas are usually preferred, which, as can be appreciated, ultimatelypresents a design challenge to instrument manufacturers who must findways to make endoscopic instruments that fit through the smallercannulas.

[0004] Many endoscopic surgical procedures require cutting or ligatingblood vessels or vascular tissue. Due to the inherent spatialconsiderations of the surgical cavity, surgeons often have difficultysuturing vessels or performing other traditional methods of controllingbleeding, e.g., clamping and/or tying-off transected blood vessels. Byutilizing an endoscopic electrosurgical forceps, a surgeon can eithercauterize, coagulate/desiccate and/or simply reduce or slow bleedingsimply by controlling the intensity, frequency and duration of theelectrosurgical energy applied through the jaw members to the tissue.Most small blood vessels, i.e., in the range below two millimeters indiameter, can often be closed using standard electrosurgical instrumentsand techniques. However, if a larger vessel is ligated, it may benecessary for the surgeon to convert the endoscopic procedure into anopen-surgical procedure and thereby abandon the benefits of endoscopicsurgery. Alternatively, the surgeon can seal the larger vessel ortissue.

[0005] It is thought that the process of coagulating vessels isfundamentally different than electrosurgical vessel sealing. For thepurposes herein, “coagulation” is defined as a process of desiccatingtissue wherein the tissue cells are ruptured and dried. “Vessel sealing”or “tissue sealing” is defined as the process of liquefying the collagenin the tissue so that it reforms into a fused mass. Coagulation of smallvessels is sufficient to permanently close them, while larger vesselsneed to be sealed to assure permanent closure.

[0006] In order to effectively seal larger vessels (or tissue) twopredominant mechanical parameters must be accurately controlled—thepressure applied to the vessel (tissue) and the gap distance between theelectrodes—both of which are affected by the thickness of the sealedvessel. More particularly, accurate application of pressure is importantto oppose the walls of the vessel; to reduce the tissue impedance to alow enough value that allows enough electrosurgical energy through thetissue; to overcome the forces of expansion during tissue heating; andto contribute to the end tissue thickness which is an indication of agood seal. It has been determined that a typical fused vessel wall isoptimum between 0.001 and 0.006 inches. Below this range, the seal mayshred or tear and above this range the lumens may not be properly oreffectively sealed.

[0007] With respect to smaller vessels, the pressure applied to thetissue tends to become less relevant whereas the gap distance betweenthe electrically conductive surfaces becomes more significant foreffective sealing. In other words, the chances of the two electricallyconductive surfaces touching during activation increases as vesselsbecome smaller.

[0008] Many known instruments include blade members or shearing memberswhich simply cut tissue in a mechanical and/or electromechanical mannerand are relatively ineffective for vessel sealing purposes. Otherinstruments rely on clamping pressure alone to procure proper sealingthickness and are not designed to take into account gap tolerancesand/or parallelism and flatness requirements which are parameters which,if properly controlled, can assure a consistent and effective tissueseal. For example, it is known that it is difficult to adequatelycontrol thickness of the resulting sealed tissue by controlling clampingpressure alone for either of two reasons: 1) if too much force isapplied, there is a possibility that the two poles will touch and energywill not be transferred through the tissue resulting in an ineffectiveseal; or 2) if too low a force is applied the tissue may pre-maturelymove prior to activation and sealing and/or a thicker, less reliableseal may be created.

[0009] As mentioned above, in order to properly and effectively seallarger vessels or tissue, a greater closure force between opposing jawmembers is required. It is known that a large closure force between thejaws typically requires a large moment about the pivot for each jaw.This presents a design challenge because the jaw members are typicallyaffixed with pins which are positioned to have small moment arms withrespect to the pivot of each jaw member. A large force, coupled with asmall moment arm, is undesirable because the large forces may shear thepins. As a result, designers must compensate for these large closureforces by either designing instruments with metal pins and/or bydesigning instruments which at least partially offload these closureforces to reduce the chances of mechanical failure. As can beappreciated, if metal pivot pins are employed, the metal pins must beinsulated to avoid the pin acting as an alternate current path betweenthe jaw members which may prove detrimental to effective sealing.

[0010] Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another which may result in a short circuitand a small closure force may cause pre-mature movement of the tissueduring compression and prior to activation. As a result thereof,providing an instrument which consistently provides the appropriateclosure force between opposing electrode within a preferred pressurerange will enhance the chances of a successful seal. As can beappreciated, relying on a surgeon to manually provide the appropriateclosure force within the appropriate range on a consistent basis wouldbe difficult and the resultant effectiveness and quality of the seal mayvary. Moreover, the overall success of creating an effective tissue sealis greatly reliant upon the user's expertise, vision, dexterity, andexperience in judging the appropriate closure force to uniformly,consistently and effectively seal the vessel. In other words, thesuccess of the seal would greatly depend upon the ultimate skill of thesurgeon rather than the efficiency of the instrument.

[0011] It has been found that the pressure range for assuring aconsistent and effective seal is between about 3 kg/cm² to about 16kg/cm² and, preferably, within a working range of 7 kg/cm² to 13 kg/cm².Manufacturing an instrument which is capable of providing a closurepressure within this working range has been shown to be effective forsealing arteries, tissues and other vascular bundles.

[0012] Various force-actuating assemblies have been developed in thepast for providing the appropriate closure forces to effect vesselsealing. For example, one such actuating assembly has been developed byValleylab Inc., a division of Tyco Healthcare LP, for use withValleylab's vessel sealing and dividing instrument commonly sold underthe trademark LIGASURE ATLAS®. This assembly includes a four-barmechanical linkage, a spring and a drive assembly which cooperate toconsistently provide and maintain tissue pressures within the aboveworking ranges. The LIGASURE ATLAS® is presently designed to fit througha 10 mm cannula and includes a bi-lateral jaw closure mechanism which isactivated by a foot switch. A trigger assembly extends a knife distallyto separate the tissue along the tissue seal. A rotating mechanism isassociated with distal end of the handle to allow a surgeon toselectively rotate the jaw members to facilitate grasping tissue.Co-pending U.S. application Ser. Nos. 10/179,863 and 10/116,944 and PCTapplication Ser. Nos. PCT/US01/01890 and PCT/7201/11340 describe indetail the operating features of the LIGASURE ATLAS® and various methodsrelating thereto. The contents of all of these applications are herebyincorporated by reference herein.

[0013] It would be desirous to develop a smaller, simpler endoscopicvessel sealing instrument which can be utilized with a 5 mm cannula.Preferably, the instrument would include a simpler and more mechanicallyadvantageous drive assembly to facilitate grasping and manipulatingvessels and tissue. In addition, it would be desirous to manufacture aninstrument which includes a hand switch and a unilateral jaw closuremechanism.

SUMMARY

[0014] The present disclosure relates to an endoscopic bipolar forcepswhich is designed to be utilized with a 5 mm trocar or cannula andincludes a housing and a shaft affixed to the distal end of the housing.Preferably, the shaft includes a reduced diameter such that the shaft isfreely insertable through the trocar. The shaft also includes alongitudinal axis defined therethrough and a pair of first and secondjaw members attached to a distal end thereof. The forceps includes adrive assembly for moving the first jaw member relative to the secondmember from a first position wherein the jaw members are disposed inspaced relation relative to each other to a second position wherein thejaw members cooperate to grasp tissue therebetween. A movable handle isincluded which is rotatable about a pivot located above the longitudinalaxis of the shaft. Movement of the handle engages a drive flange intomechanical cooperation with the drive assembly to move the jaw membersfrom the open and closed positions. Advantageously, the pivot is locateda fixed distance above the longitudinal axis to provide lever-likemechanical advantage to the drive flange. The drive flange is locatedgenerally along the longitudinal axis. The forceps is connected to asource of electrosurgical energy which carries electrical potentials toeach respective jaw member such that the jaw members are capable ofconducting bipolar energy through tissue held therebetween to effect atissue seal.

[0015] In yet another embodiment, the forceps includes a hand switchdisposed within the housing which is electromechanically connected tothe energy source. Advantageously, the hand switch allows a user toselectively supply bipolar energy to the jaw members to effect a tissueseal.

[0016] In one embodiment, the forceps includes a selectively advanceableknife assembly for cutting tissue in a forward direction along thetissue seal. A rotating assembly may also be included for rotating thejaw members about the longitudinal axis defined through the shaft.Advantageously, the rotating assembly is located proximal to the drivingflange and near the hand switch to facilitate rotation.

[0017] Preferably, the movable jaw member includes a first electricalpotential and the fixed jaw member includes a second electricalpotential. A lead connects the movable jaw member to the first potentialand a conductive tube (which is disposed through the shaft) conducts asecond electrical potential to the fixed jaw member. Advantageously, theconductive tube is connected to the rotating assembly to permitselective rotation of the jaw members.

[0018] In one embodiment, the drive assembly includes a reciprocatingsleeve which upon activation of the movable handle, translates atop therotating conductive tube to move the movable jaw member relative to thefixed jaw member. Preferably, the movable jaw member includes a detentwhich extends beyond the fixed jaw member which is designed forengagement with the reciprocating sleeve such that, upon translationthereof, the movable jaw member moves relative to the fixed jaw member.Advantageously, a spring is included with the drive assembly tofacilitate actuation of the movable handle and to assure the closureforce is maintained within the working range of about 3 kg/cm² to about16 kg/cm² and, preferably, about 7 kg/cm² to about 13 kg/cm²

[0019] Preferably, at least one of the jaw members includes a series ofstop members disposed thereon for regulating the distance between thejaw members (i.e., creating a gap between the two opposing jaw members)during the sealing process. As can be appreciated, regulating the gapdistance between opposing jaw members along with maintaining the closingpressure to within the above-described ranges will produce a reliableand consistent tissue seal.

[0020] The present disclosure also relates to an endoscopic bipolarforceps which includes a shaft having a movable jaw member and a fixedjaw member at a distal end thereof. The forceps also includes a driveassembly for moving the movable jaw member relative to the fixed jawmember from a first position wherein the movable jaw member is disposedin spaced relation relative to the fixed jaw member to a second positionwherein the movable jaw member is closer to the fixed jaw member formanipulating tissue. A movable handle is included which actuates thedrive assembly to move the movable jaw member.

[0021] The forceps connects to a source of electrosurgical energy whichis conducted to each jaw member such that the jaw members are capable ofconducting bipolar energy through tissue held therebetween to effect atissue seal. Advantageously, the forceps also includes a selectivelyadvanceable knife assembly for cutting tissue in a distal directionalong the tissue seal and a stop member disposed on at least one of thejaw members for regulating the distance between jaw members duringsealing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various embodiments of the subject instrument are describedherein with reference to the drawings wherein:

[0023]FIG. 1 is a left, perspective view of an endoscopic bipolarforceps showing a housing, a shaft and an end effector assemblyaccording to the present disclosure;

[0024]FIG. 2 is a top view of the forceps of FIG. 1;

[0025]FIG. 3 is a left, side view of the forceps of FIG. 1;

[0026]FIG. 4 is a left, perspective view of the forceps of FIG. 1showing the rotation of the end effector assembly about a longitudinalaxis “A”;

[0027]FIG. 5 is a front view of the forceps of FIG. 1;

[0028] FIGS. 6 is an enlarged view of the indicated area of detail ofFIG. 5 showing an enhanced view of the end effector assembly detailing apair of opposing jaw members;

[0029]FIG. 7 is an enlarged, rear perspective view of the housing;

[0030]FIG. 8 is an enlarged, left perspective view of the end effectorassembly with the jaw members shown in open configuration;

[0031]FIG. 9 is an enlarged, side view of the end effector assembly;

[0032]FIG. 10 is an enlarged, perspective view of the underside of theupper jaw member of the end effector assembly;

[0033]FIG. 11 is an enlarged, broken perspective view showing the endeffector assembly and highlighting a cam-like closing mechanism whichcooperates with a reciprocating pull sleeve to move the jaw membersrelative to one another;

[0034]FIG. 12 is a full perspective view of the end effector assembly ofFIG. 11;

[0035]FIG. 13 is an enlarged, perspective view of the housing and theinternal working components thereof;

[0036]FIG. 14 is top, perspective view of the housing of FIG. 13 withparts separated;

[0037]FIG. 15 is a left, perspective view of a rotating assembly, driveassembly, knife assembly and lower jaw member according to the presentdisclosure;

[0038]FIG. 16 is a rear, perspective view of the rotating assembly,drive assembly and knife assembly;

[0039]FIG. 17 is an enlarged, top, perspective view of the end effectorassembly with parts separated;

[0040]FIG. 18 is an enlarged, perspective view of the knife assembly;

[0041]FIG. 19 is an enlarged, perspective view of the rotating assembly;

[0042]FIG. 20 is an enlarged, perspective view of the drive assembly;

[0043]FIG. 21 is an enlarged, perspective view of the knife assemblywith parts separated;

[0044]FIG. 22 is an enlarged view of the indicated area of detail ofFIG. 21;

[0045]FIG. 23 is a greatly-enlarged, perspective view of a distal end ofthe knife assembly;

[0046]FIG. 24 is a greatly-enlarged, perspective view of a knife driveof the knife assembly;

[0047]FIG. 25 is an enlarged, perspective view of the rotating assemblyand lower jaw member with parts separated;

[0048]FIG. 26 is a cross section of the area indicated in detail in FIG.25;

[0049]FIG. 27 is a greatly-enlarged, perspective view of the lower jawmember;

[0050]FIG. 28 is an enlarged, perspective view of the drive assembly;

[0051]FIG. 29 is an enlarged perspective view of the drive assembly ofFIG. 28 with parts separated;

[0052]FIG. 30 is an internal, side view of the housing showing theinner-working components thereof;

[0053]FIG. 31 is a cross-section of the housing with the end effectorshown in open configuration and showing the internal, electrical routingof an electrosurgical cable and electrical leads;

[0054]FIG. 32 is a greatly-enlarged view of the indicated area of detailof FIG. 31;

[0055]FIG. 33 is a greatly-enlarged view of the indicated area of detailof FIG. 31;

[0056]FIG. 34 is a greatly-enlarged, cross section of the shaft takenalong line 34-34;

[0057]FIG. 35 is a side, cross section of the shaft and end effectorassembly;

[0058]FIG. 36 is a perspective view showing the forceps of the presentdisclosure being utilized with a 5 mm cannula;

[0059]FIG. 37 is a side, cross section of the housing showing the movingcomponents of the drive assembly during actuation;

[0060]FIG. 38 is a greatly-enlarged, perspective view of a handlelocking mechanism for use with the drive assembly;

[0061]FIG. 39 is a greatly-enlarged view of the indicated area of detailin FIG. 37;

[0062]FIG. 40 is a greatly-enlarged view of the indicated area of detailin FIG. 37;

[0063]FIG. 41 is an enlarged, rear, perspective view of the endeffectors shown grasping tissue;

[0064]FIG. 42 is an enlarged view of a tissue seal;

[0065]FIG. 43 is a side, cross section of a tissue seal;

[0066]FIG. 44 is a cross section of the housing with the handle in alocked configuration and showing the moving components of the knifeassembly during activation;

[0067]FIG. 45 is an enlarged view of the area indicated in detail inFIG. 44;

[0068]FIG. 46 is a side, cross section of a tissue seal after separationby the knife assembly;

[0069]FIG. 47 is a side, cross section of the housing showing therelease of the knife assembly and release of the drive assembly to openthe jaw members and release the tissue;

[0070]FIG. 48 is a greatly-enlarged view of the indicated area of detailin FIG. 47; and

[0071]FIG. 49 is a greatly-enlarged view of the indicated area of detailin FIG. 47.

DETAILED DESCRIPTION

[0072] Turning now to FIGS. 1-3, one embodiment of an endoscopic bipolarforceps 10 is shown for use with various surgical procedures andgenerally includes a housing 20, a handle assembly 30, a rotatingassembly 80, a trigger assembly 70 and an end effector assembly 100which mutually cooperate to grasp, seal and divide tubular vessels andvascular tissue 420 (FIG. 36). Although the majority of the figuredrawings depict a bipolar forceps 10 for use in connection withendoscopic surgical procedures, the present disclosure may be used formore traditional open surgical procedures. For the purposes herein, theforceps 10 is described in terms of an endoscopic instrument, however,it is contemplated that an open version of the forceps may also includethe same or similar operating components and features as describedbelow.

[0073] Forceps 10 includes a shaft 12 which has a distal end 16dimensioned to mechanically engage the end effector assembly 100 and aproximal end 14 which mechanically engages the housing 20. Details ofhow the shaft 12 connects to the end effector are described in moredetail below with respect to FIG. 25. The proximal end 14 of shaft 12 isreceived within the housing 20 and the connections relating thereto aredescribed in detail below with respect to FIGS. 13 and 14. In thedrawings and in the descriptions which follow, the term “proximal”, asis traditional, will refer to the end of the forceps 10 which is closerto the user, while the term “distal” will refer to the end which isfurther from the user.

[0074] As best seen in FIG. 1, forceps 10 also includes anelectrosurgical cable 310 which connects the forceps 10 to a source ofelectrosurgical energy, e.g., a generator (not shown). Preferably,generators such as those sold by Valleylab—a division of Tyco HealthcareLP, located in Boulder Colo. are used as a source of electrosurgicalenergy, e.g., FORCE EZ™ Electrosurgical Generator, FORCE FX™Electrosurgical Generator, FORCE 1C™ , FORCE 2™ Generator, SurgiStat™II. One such system is described in commonly-owned U.S. Pat. No.6,033,399 entitled “ELECTROSURGICAL GENERATOR WITH ADAPTIVE POWERCONTROL” the entire contents of which are hereby incorporated byreference herein. Other systems have been described in commonly-ownedU.S. Pat. No. 6,187,003 entitled “BIPOLAR ELECTROSURGICAL INSTRUMENT FORSEALING VESSELS” the entire contents of which is also incorporated byreference herein.

[0075] Preferably, the generator includes various safety and performancefeatures including isolated output, independent activation ofaccessories. Preferably, the electrosurgical generator includesValleylab's Instant Response™ technology features which provides anadvanced feedback system to sense changes in tissue 200 times per secondand adjust voltage and current to maintain appropriate power. TheInstant Response™ technology is believed to provide one or more of thefollowing benefits to surgical procedure:

[0076] Consistent clinical effect through all tissue types;

[0077] Reduced thermal spread and risk of collateral tissue damage;

[0078] Less need to “turn up the generator”; and

[0079] Designed for the minimally invasive environment.

[0080] Cable 310 is internally divided into cable lead 310 a, 310 b and310 c which each transmit electrosurgical energy through theirrespective feed paths through the forceps 10 to the end effectorassembly 100 as explained in more detail below with respect to FIGS. 14and 30.

[0081] Handle assembly 30 includes a fixed handle 50 and a movablehandle 40. Fixed handle 50 is integrally associated with housing 20 andhandle 40 is movable relative to fixed handle 50 as explained in moredetail below with respect to the operation of the forceps 10. Rotatingassembly 80 is preferably integrally associated with the housing 20 andis rotatable approximately 180 degrees in either direction about alongitudinal axis “A” (See FIG. 4). Details of the rotating assembly 80are described in more detail with respect to FIGS. 13, 14, 15 and 16

[0082] As best seen in FIGS. 2, 13 and 14, housing 20 is formed from two(2) housing halves 20 a and 20 b which each include a plurality ofinterfaces 27 a-27 f which are dimensioned to mechanically align andengage one another to form housing 20 and enclose the internal workingcomponents of forceps 10. As can be appreciated, fixed handle 50 which,as mentioned above, is integrally associated with housing 20, takesshape upon the assembly of the housing halves 20 a and 20 b.

[0083] It is envisioned that a plurality of additional interfaces (notshown) may disposed at various points around the periphery of housinghalves 20 a and 20 b for ultrasonic welding purposes, e.g., energydirection/deflection points. It is also contemplated that housing halves20 a and 20 b (as well as the other components described below) may beassembled together in any fashion known in the art. For example,alignment pins, snap-like interfaces, tongue and groove interfaces,locking tabs, adhesive ports, etc. may all be utilized either alone orin combination for assembly purposes.

[0084] Rotating assembly 80 includes two halves 82 a and 82 b which,when assembled, form the rotating assembly 80 which, in turn, houses thedrive assembly 150 and the knife assembly 140 (See FIGS. 13, 14 and 25).Half 80 a includes a series of detents/flanges 375 a, 375 b, 375 c and375 d (FIG. 25) which are dimensioned to engage a pair of correspondingsockets or other mechanical interfaces (not shown) disposed withinrotating half 80 a. Movable handle 40 and trigger assembly 70 arepreferably of unitary construction and are operatively connected to thehousing 20 and the fixed handle 50 during the assembly process.

[0085] As mentioned above, end effector assembly 100 is attached at thedistal end 14 of shaft 12 and includes a pair of opposing jaw members110 and 120. Movable handle 40 of handle assembly 30 is ultimatelyconnected to a drive assembly 150 which, together, mechanicallycooperate to impart movement of the jaw members 110 and 120 from an openposition wherein the jaw members 110 and 120 are disposed in spacedrelation relative to one another, to a clamping or closed positionwherein the jaw members 110 and 120 cooperate to grasp tissue 420 (FIG.36) therebetween.

[0086] It is envisioned that the forceps 10 may be designed such that itis fully or partially disposable depending upon a particular purpose orto achieve a particular result. For example, end effector assembly 100may be selectively and releasably engageable with the distal end 16 ofthe shaft 12 and/or the proximal end 14 of shaft 12 may be selectivelyand releasably engageable with the housing 20 and the handle assembly30. In either of these two instances, the forceps 10 would be considered“partially disposable” or “reposable”, i.e., a new or different endeffector assembly 100 (or end effector assembly 100 and shaft 12)selectively replaces the old end effector assembly 100 as needed. As canbe appreciated, the presently disclosed electrical connections wouldhave to be altered to modify the instrument to a reposable forceps.

[0087] Turning now to the more detailed features of the presentdisclosure as described with respect to FIGS. 1-14, movable handle 40includes a finger loop 41 which has an aperture 42 defined therethroughwhich enables a user to grasp and move the handle 40 relative to thefixed handle 50. Handle 40 also includes an ergonomically-enhancedgripping element 43 disposed along the inner peripheral edge of aperture42 which is designed to facilitate gripping of the movable handle 40during activation. It is envisioned that gripping element 43 may includeone or more protuberances, scallops and/or ribs to enhance gripping. Asbest seen in FIG. 14, movable handle 40 is selectively moveable about apair of pivot pins 29 a and 29 b from a first position relative to fixedhandle 50 to a second position in closer proximity to the fixed handle50 which, as explained below, imparts movement of the jaw members 110and 120 relative to one another. The movable handle include a clevis 45which forms a pair of upper flanges 45 a and 45 b each having anaperture 49 a and 49 b, respectively, at an upper end thereof forreceiving the pivot pins 29 a and 29 b therethrough and mounting theupper end of the handle 40 to the housing 20. In turn, each pin 29 a and29 b mounts to a respective housing half 20 a and 20 b.

[0088] Each upper flange 45 a and 45 b also includes a force-actuatingflange or drive flange 47 a and 47 b, respectively, which are alignedalong longitudinal axis “A” and which abut the drive assembly 150 suchthat pivotal movement of the handle 40 forces actuating flange againstthe drive assembly 150 which, in turn, closes the jaw members 110 and120. For the purposes herein, 47 a and 47 b which act simultaneously onthe drive assembly are referred to as “driving flange 47”. A moredetailed explanation of the inter-cooperating components of the handleassembly 30 and the drive assembly 150 is discussed below.

[0089] As best seen in FIG. 14, the lower end of the movable handle 40includes a flange 90 which is preferably mounted to the movable handle40 by pins 94 a and 94 b which engage a corresponding pair of apertures91 a and 91 b disposed within the lower portion of handle 40 andapertures 97 a and 97 b disposed within flange 90, respectively. Othermethods of engagement are also contemplated, snap-lock, spring tab, etc.Flange 90 also includes a t-shaped distal end 95 which rides within apredefined channel 51 disposed within fixed handle 50 to lock themovable handle 40 relative to the fixed handle 50. Additional featureswith respect to the t-shaped end 95 are explained below in the detaileddiscussion of the operational features of the forceps 10.

[0090] Movable handle 40 is designed to provide a distinct mechanicaladvantage over conventional handle assemblies due to the unique positionof the pivot pins 29 a and 29 b (i.e., pivot point) relative to thelongitudinal axis “A” of the shaft 12 and the disposition of the drivingflange 47 along longitudinal axis “A”. In other words, it is envisionedthat by positioning the pivot pins 29 a and 29 b above the drivingflange 47, the user gains lever-like mechanical advantage to actuate thejaw members 110 and 120 enabling the user to close the jaw members 110and 120 with lesser force while still generating the required forcesnecessary to effect a proper and effective tissue seal. It is alsoenvisioned that the unilateral design of the end effector assembly 100will also increase mechanical advantage as explained in more detailbelow.

[0091] As shown best in FIGS. 6-12, the end effector assembly 100includes opposing jaw members 110 and 120 which cooperate to effectivelygrasp tissue 420 for sealing purposes. The end effector assembly 100 isdesigned as a unilateral assembly, i.e., jaw member 120 is fixedrelative to the shaft 12 and jaw member 110 pivots about a pivot pin 103to grasp tissue 420.

[0092] More particularly, the unilateral end effector assembly 100includes one stationary or fixed jaw member 120 mounted in fixedrelation to the shaft 12 and pivoting jaw member 110 mounted about apivot pin 103 attached to the stationary jaw member 120. A reciprocatingsleeve 60 is slidingly disposed within the shaft 12 and is remotelyoperable by the drive assembly 150. The pivoting jaw member 110 includesa detent or protrusion 117 which extends from jaw member 110 through anaperture 62 disposed within the reciprocating sleeve 60 (FIG. 12). Thepivoting jaw member 110 is actuated by sliding the sleeve 60 axiallywithin the shaft 12 such that a distal end 63 of the aperture 62 abutsagainst the detent 117 on the pivoting jaw member 110 (See FIGS. 11 and12). Pulling the sleeve 60 proximally closes the jaw members 110 and 120about tissue 420 grasped therebetween and pushing the sleeve 60 distallyopens the jaw members 110 and 120 for grasping purposes.

[0093] As best illustrated in FIGS. 8 and 10, a knife channel 115 a and115 b runs through the center of the jaw members 110 and 120,respectively, such that a blade 185 from the knife assembly 140 can cutthe tissue 420 grasped between the jaw members 110 and 120 when the jawmembers 110 and 120 are in a closed position. More particularly, theblade 185 can only be advanced through the tissue 420 when the jawmembers 110 and 120 are closed thus preventing accidental or prematureactivation of the blade 185 through the tissue 420. Put simply, theknife channel 115 (made up of half channels 115 a and 115 b) is blockedwhen the jaws members 110 and 120 are opened and aligned for distalactivation when the jaw members 110 and 120 are closed (See FIGS. 35 and39). It is also envisioned that the unilateral end effector assembly 100may be structured such that electrical energy can be routed through thesleeve 60 at the protrusion 117 contact point with the sleeve 60 orusing a “brush” or lever (not shown) to contact the back of the movingjaw member 110 when the jaw member 110 closes. In this instance, theelectrical energy would be routed through the protrusion 117 to thestationary jaw member 120. Alternatively, the cable lead 311 may berouted to energize the stationary jaw member 120 and the otherelectrical potential may be conducted through the sleeve 60 andtransferred to the pivoting jaw member 110 which establishes electricalcontinuity upon retraction of the sleeve 60. It is envisioned that thisparticular envisioned embodiment will provide at least two importantsafety features: 1) the blade 185 cannot extend while the jaw members110 and 120 are opened; and 2) electrical continuity to the jaw members110 and 120 is made only when the jaw members are closed. Theillustrated forceps 10 only includes the novel knife channel 115.

[0094] As best shown in FIG. 8, jaw member 110 also includes a jawhousing 116 which has an insulative substrate or insulator 114 and anelectrically conducive surface 112. Insulator 114 is preferablydimensioned to securely engage the electrically conductive sealingsurface 112. This may be accomplished by stamping, by overmolding, byovermolding a stamped electrically conductive sealing plate and/or byovermolding a metal injection molded seal plate. For example and asshown in FIG. 17, the electrically conductive sealing plate 112 includesa series of upwardly extending flanges 111 a and 111 b which aredesigned to matingly engage the insulator 114. The insulator 114includes a shoe-like interface 107 disposed at a distal end thereofwhich is dimensioned to engage the outer periphery 116 a of the housing116 in a slip-fit manner. The shoe-like interface 107 may also beovermolded about the outer periphery of the jaw 110 during amanufacturing step. It is envisioned that lead 311 terminates within theshoe-like interface 107 at the point where lead 311 electricallyconnects to the seal plate 112 (not shown). The movable jaw member 110also includes a wire channel 113 which is designed to guide cable lead311 into electrical continuity with sealing plate 112 as described inmore detail below.

[0095] All of these manufacturing techniques produce jaw member 110having an electrically conductive surface 112 which is substantiallysurrounded by an insulating substrate 114. The insulator 114,electrically conductive sealing surface 112 and the outer,non-conductive jaw housing 116 are preferably dimensioned to limitand/or reduce many of the known undesirable effects related to tissuesealing, e.g., flashover, thermal spread and stray current dissipation.Alternatively, it is also envisioned that the jaw members 110 and 120may be manufactured from a ceramic-like material and the electricallyconductive surface(s) 112 are coated onto the ceramic-like jaw members110 and 120.

[0096] Jaw member 110 includes a pivot flange 118 which includesprotrusion 117. Protrusion 1 17 extends from pivot flange 118 andincludes an arcuately-shaped inner surface 111 dimensioned to matinglyengage the aperture 62 of sleeve 60 upon retraction thereof. Pivotflange 118 also includes a pin slot 119 which is dimensioned to engagepivot pin 103 to allow jaw member 110 to rotate relative to jaw member120 upon retraction of the reciprocating sleeve 60. As explained in moredetail below, pivot pin 103 also mounts to the stationary jaw member 120through a pair of apertures 101 a and 101 b disposed within a proximalportion of the jaw member 120.

[0097] It is envisioned that the electrically conductive sealing surface112 may also include an outer peripheral edge which has a pre-definedradius and the insulator 114 meets the electrically conductive sealingsurface 112 along an adjoining edge of the sealing surface 112 in agenerally tangential position. Preferably, at the interface, theelectrically conductive surface 112 is raised relative to the insulator114. These and other envisioned embodiments are discussed in co-pending,commonly assigned application Ser. No. PCT/US01/11412 entitled“ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATERAL DAMAGE TO ADJACENTTISSUE” by Johnson et al. and co-pending, commonly assigned applicationSer. No. PCT/US01/11411 entitled “ELECTROSURGICAL INSTRUMENT WHICH ISDESIGNED TO REDUCE THE INCIDENCE OF FLASHOVER” by Johnson et al.

[0098] Preferably, the electrically conductive surface 112 and theinsulator 114, when assembled, form a longitudinally-oriented slot 115 adefined therethrough for reciprocation of the knife blade 185. It isenvisioned that the knife channel 115 a cooperates with a correspondingknife channel 115 b defined in stationary jaw member 120 to facilitatelongitudinal extension of the knife blade 185 along a preferred cuttingplane to effectively and accurately separate the tissue 420 along theformed tissue seal 450 (See FIGS. 42 and 46).

[0099] Jaw member 120 includes similar elements to jaw member 110 suchas jaw housing 126 having an insulator 124 and an electricallyconductive sealing surface 122 which is dimensioned to securely engagethe insulator 124. Likewise, the electrically conductive surface 122 andthe insulator 124, when assembled, include a longitudinally-orientedchannel 115 a defined therethrough for reciprocation of the knife blade185. As mentioned above, when the jaw members 110 and 120 are closedabout tissue 420, knife channels 115 a and 115 b form a complete knifechannel 115 to allow longitudinal extension of the knife 185 in a distalfashion to sever tissue 420 along the tissue seal 450. It is alsoenvisioned that the knife channel 115 may be completely disposed in oneof the two jaw members, e.g., jaw member 120, depending upon aparticular purpose. It is envisioned that the fixed jaw member 120 maybe assembled in a similar manner as described above with respect to jawmember 110.

[0100] As best seen in FIG. 8, jaw member 120 includes a series of stopmembers 750 preferably disposed on the inner facing surfaces of theelectrically conductive sealing surface 122 to facilitate gripping andmanipulation of tissue and to define a gap “G” (FIG. 24) betweenopposing jaw members 110 and 120 during sealing and cutting of tissue.It is envisioned that the series of stop members 750 may be employed onone or both jaw members 110 and 120 depending upon a particular purposeor to achieve a desired result. A detailed discussion of these and otherenvisioned stop members 750 as well as various manufacturing andassembling processes for attaching and/or affixing the stop members 750to the electrically conductive sealing surfaces 112, 122 are describedin commonly-assigned, co-pending U.S. application Ser. No.PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITH NON-CONDUCTIVESTOP MEMBERS” by Dycus et al. which is hereby incorporated by referencein its entirety herein.

[0101] Jaw member 120 is designed to be fixed to the end of a rotatingtube 160 which is part of the rotating assembly 80 such that rotation ofthe tube 160 will impart rotation to the end effector assembly 100 (SeeFIGS. 25 and 27). Jaw member 120 includes a rear C-shaped cuff 170having a slot 177 defined therein which is dimensioned to receive aslide pin 171. More particularly, slide pin 171 includes a slide rail176 which extends substantially the length thereof which is dimensionedto slide into friction-fit engagement within slot 177. A pair ofchamfered plates 172 a and 172 b extend generally radially from theslide rail 176 and include a radius which is substantially the sameradius as the outer periphery of the rotating tube 160 such that theshaft 12 can encompass each of the same upon assembly.

[0102] As explained in more detail below, fixed jaw member 120 isconnected to a second electrical potential through tube 160 which isconnected at its proximal end to lead 310 c. More particularly, fixedjaw 120 is welded to the rotating tube 160 and includes a fuse clip,spring clip or other electro-mechanical connection which provideselectrical continuity to the fixed jaw member 120 from lead 310 c (SeeFIG. 32). As best shown in FIGS. 25 and 26, the rotating tube 160includes an elongated guide slot 167 disposed in an upper portionthereof which is dimensioned to carry lead 311 therealong. The chamferedplates 172 a and 172 b also form a wire channel 175 which is dimensionedto guide the cable lead 311 from the tube 160 and into the movable jawmember 110 (See FIG. 8). Lead 311 carries a first electrical potentialto movable jaw 110. As explained in more detail below with respect tothe internal electrical connections of the forceps, a second electricalconnection from lead 310 c is conducted through the tube 160 to thefixed jaw member 120.

[0103] As shown in FIG. 25, the distal end of the tube 160 is generallyC-shaped to include two upwardly extending flanges 162 a and 162 b whichdefine a cavity 165 for receiving the proximal end of the fixed jawmember 120 inclusive of C-shaped cuff 170 and slide pin 171 (See FIG.27). Preferably, the tube cavity 165 retains and secures the jaw member120 in a friction-fit manner, however, the jaw member 120 may be weldedto the tube 160 depending upon a particular purpose. Tube 160 alsoincludes an inner cavity 169 defined therethrough which reciprocates theknife assembly 140 upon distal activation thereof and an elongated guiderail 163 which guides the knife assembly 140 during distal activation.The details with respect to the knife assembly are explained in moredetail with respect to FIGS. 21-24. The proximal end of tube 160includes a laterally oriented slot 168 which is designed to interfacewith the rotating assembly 80 as described below.

[0104]FIG. 25 also shows the rotating assembly 80 which includesC-shaped rotating halves 82 a and 82 b which, when assembled about tube160, form a generally circular rotating member 82. More particularly,each rotating half, e.g., 82 b, includes a series of mechanicalinterfaces 375 a, 375 b, 375 c and 375 d which matingly engage acorresponding series of mechanical interfaces in half 82 a to formrotating member 82. Half 82 b also includes a tab 89 b which togetherwith a corresponding tab 89 a disposed on half 82 a (phantomlyillustrated) cooperate to matingly engage slot 168 disposed on tube 160.As can be appreciated, this permits selective rotation of the tube 160about axis “A” by manipulating the rotating member 82 in the directionof the arrow “B” (see FIG. 4).

[0105] As best shown in the exploded view of FIG. 17, jaw members 110and 120 are pivotably mounted with respect to one another such that jawmember 110 pivots in a unilateral fashion from a first open position toa second closed position for grasping and manipulating tissue 420. Moreparticularly, fixed jaw member 120 includes a pair of proximal, upwardlyextending flanges 125 a and 125 b which define a cavity 121 dimensionedto receive flange 118 of movable jaw member 110 therein. Each of theflanges 125 a and 125 b includes an aperture 101 a and 101 b,respectively, defined therethrough which secures pivot pin 103 onopposite sides of pivot mount 119 disposed within jaw member 110. Asexplained in detail below with respect to the operation of the jawmembers 110 and 120, proximal movement of the tube 60 engages detent 117to pivot the jaw member 110 to a closed position.

[0106]FIGS. 13 and 14 show the details of the housing 20 and thecomponent features thereof, namely, the drive assembly 150, the rotatingassembly 80, the knife assembly 140, the trigger assembly 70 and thehandles 40 and 50. More particularly, FIG. 13 shows the above-identifiedassemblies and components in an assembled form in the housing 20 andFIG. 14 shows an exploded view of each of the above-identifiedassemblies and components.

[0107] As shown best in FIG. 14, the housing includes halves 20 a and 20b which, when mated, form housing 20. As can be appreciated, housing 20,once formed, houses the various assemblies identified above which willenable a user to selectively manipulate, grasp, seal and sever tissue420 in a simple, effective, and efficient manner. Preferably, each halfof the housing, e.g., half 20 b, includes a series of mechanicalinterfacing component, e.g., 27 a-27 f which align and/or mate with acorresponding series of mechanical interfaces (not shown) to align thetwo housing halves 20 a and 20 b about the inner components andassemblies. The housing halves 20 a and 20 b are then preferably sonicwelded to secure the housing halves 20 a and 20 b once assembled.

[0108] As mentioned above, the movable handle 40 includes clevis 45which forms upper flanges 45 a and 45 b which pivot about pins 29 a and29 b to pull the reciprocating sleeve 60 along longitudinal axis “A” andforce during flange 47 against the drive assembly 150 which, in turn,closes the jaw members 110 and 120. As mentioned above, the lower end ofthe movable handle 40 includes a flange 90 which has a t-shaped distalend 95 which rides within a predefined channel 51 disposed within fixedhandle 50 to lock the movable handle 40 in a preset orientation relativeto the fixed handle 50. The arrangement of the upper flanges 45 a and 45b and the pivot point of the movable handle 40 provides a distinctmechanical advantage over conventional handle assemblies due to theunique position of the pivot pins 29 a and 29 b (i.e., pivot point)relative to the longitudinal axis “A” of the driving flange 47. In otherwords, by positioning the pivot pins 29 a and 29 b above the drivingflange 47, the user gains lever-like mechanical advantage to actuate thejaw members 110 and 120. This reduces the overall amount of mechanicalforce necessary to close the jaw members 110 and 120 to effect a tissueseal.

[0109] Handle 40 also includes a finger loop 41 which defines opening 42which is dimensioned to facilitate grasping the handle 40. Preferably,finger loop 41 includes rubber insert 43 which enhances the overallergonomic “feel” of the handle member 40. A locking flange 44 isdisposed on the outer periphery of the handle member 40 above the fingerloop 41. Locking flange 44 prevents the trigger assembly 70 from firingwhen the handle member 40 is oriented in a non-actuated position, i.e.,the jaw members 110 and 120 are open. As can be appreciated, thisprevents accidental or premature severing of tissue 420 prior tocompletion of the tissue seal 450.

[0110] Fixed handle 50 includes halves 50 a and 50 b which, whenassembled, form handle 50. Fixed handle 50 includes a channel 51 definedtherein which is dimensioned to receive flange 90 in a proximal movingmanner when movable handle 40 is actuated. The t-shaped free end 95 ofhandle 40 is dimensioned for facile reception within channel 51 ofhandle 50. It is envisioned that flange 90 may be dimensioned to allow auser to selectively, progressively and/or incrementally move jaw members110 and 120 relative to one another from the open to closed positions.For example, it is also contemplated that flange 90 may include aratchet-like interface which lockingly engages the movable handle 40and, therefore, jaw members 110 and 120 at selective, incrementalpositions relative to one another depending upon a particular purpose.Other mechanisms may also be employed to control and/or limit themovement of handle 40 relative to handle 50 (and jaw members 110 and120) such as, e.g., hydraulic, semi-hydraulic, linear actuator(s),gas-assisted mechanisms and/or gearing systems.

[0111] As best illustrated in FIG. 13, housing halves 20 a and 20 b whenassembled form an internal cavity 52 which predefines the channel 51within fixed handle 50 such that an entrance pathway 54 and an exitpathway 58 are formed for reciprocation of the t-shaped flange end 95therein. When assembled, two generally triangular-shaped members 57 (onedisposed in each handle half 50 a and 50 b) are positioned in closeabutment relative to one another to define a rail or track 192therebetween. During movement of the flange 90 along the entrance andexit pathways 54 and 58, respectively, the t-shaped end 95 rides alongtrack 192 between the two triangular members 57 according to theparticular dimensions of the triangularly-shaped members 57, which, ascan be appreciated, predetermines part of the overall pivoting motion ofhandle 40 relative to fixed handle 50.

[0112] Once actuated, handle 40 moves in a generally arcuate fashiontowards fixed handle 50 about pivot pins 29 a and 29 b which forcesdriving flange 47 proximally against the drive assembly 150 which, inturn, pulls reciprocating sleeve 60 in a generally proximal direction toclose jaw member 110 relative to jaw member 120. Moreover, proximalrotation of the handle 40 causes the locking flange 44 to release, i.e.,“unlock”, the trigger assembly 70 for selective actuation. This featureis shown in detail with reference to FIGS. 33, 37 and 44 and theexplanation of the operation of the knife assembly 70 explained below.

[0113] The operating features and relative movements of the internalworking components of the forceps 10 are shown by phantom representationin the various figures. As mentioned above, when the forceps 10 isassembled a predefined channel 52 is formed within the fixed handle 50.The channel includes entrance pathway 51 and an exit pathway 58 forreciprocation of the flange 90 and the t-shaped end 95 therein. Onceassembled, the two generally triangular-shaped members 57 are positionedin close abutment relative to one another and define track 192 disposedtherebetween.

[0114] As the handle 40 is squeezed and flange 90 is incorporated intochannel 51 of fixed handle 50, the driving flange 47, through themechanical advantage of the above-the-center pivot points, biases flange154 of drive ring 159 which, in turn, compresses a spring 67 against arear ring 156 of the drive assembly 150 (FIG. 40). As a result thereof,the rear ring 156 reciprocates sleeve 60 proximally which, in turn,closes jaw member 110 onto jaw member 120. It is envisioned that theutilization of an over-the-center pivoting mechanism will enable theuser to selectively compress the coil spring 67 a specific distancewhich, in turn, imparts a specific pulling load on the reciprocatingsleeve 60 which is converted to a rotational torque about the jaw pivotpin 103. As a result, a specific closure force can be transmitted to theopposing jaw members 110 and 120.

[0115]FIGS. 37 and 38 show the initial actuation of handle 40 towardsfixed handle 50 which causes the free end 95 of flange 90 to movegenerally proximally and upwardly along entrance pathway 51. Duringmovement of the flange 90 along the entrance and exit pathways 51 and58, respectively, the t-shaped end 95 rides along track 192 between thetwo triangular members 57. Once the desired position for the sealingsite is determined and the jaw members 110 and 120 are properlypositioned, handle 40 may be compressed fully such that the t-shaped end95 of flange 90 clears a predefined rail edge 193 located atop thetriangular-shaped members 57. Once end 95 clears edge 193, releasingmovement of the handle 40 and flange 90 is redirected into a catch basin194 located at the proximal end of the triangular member 57. Moreparticularly, upon a slight reduction in the closing pressure of handle40 against handle 50, the handle 40 returns slightly distally towardsentrance pathway 51 but is re-directed towards exit pathway 58. At thispoint, the release or return pressure between the handles 40 and 50which is attributable and directly proportional to the release pressureassociated with the compression of the drive assembly 150 causes the end95 of flange 90 to settle or lock within catch basin 194. Handle 40 isnow secured in position within fixed handle 50 which, in turn, locks thejaw members 110 and 120 in a closed position against the tissue 420.

[0116] As mentioned above, the jaw members 110 and 120 may be opened,closed and rotated to manipulate tissue 420 until sealing is desired.This enables the user to position and re-position the forceps 10 priorto activation and sealing. As illustrated in FIG. 4, the end effectorassembly 100 is rotatable about longitudinal axis “A” through rotationof the rotating assembly 80. As explained in more detail below, it isenvisioned that the unique feed path of the cable lead 311 through therotating assembly 80, along shaft 12 and, ultimately, to the jaw member110 enables the user to rotate the end effector assembly 100 about 180degrees in both the clockwise and counterclockwise direction withouttangling or causing undue strain on cable lead 311. Cable lead 310 c isfused or clipped to the proximal end of tube 160 and is generallyunaffected by rotation of the jaw members 110 and 120. As can beappreciated, this facilitates the grasping and manipulation of tissue420.

[0117] Again as best shown in FIGS. 13 and 14, trigger assembly 70mounts atop movable handle 40 and cooperates with the knife assembly 140to selectively translate knife 185 through a tissue seal 450. Moreparticularly, the trigger assembly 70 includes a finger actuator 71 anda U-shaped upwardly-extending flange 74 having legs 74 a and 74 b. Apivot pin 73 mounts the trigger assembly 70 between housing halves 20 aand 20 b for selective rotation thereof. A pair of safety tabs 76 a and76 b are disposed atop finger actuator 71 and are dimensioned to abutthe locking flange 44 on handle 40 when the handle 40 is disposed in anon-actuated position, i.e., the jaw members 110 and 120 are opened.

[0118] As best seen in FIG. 14, the legs 74 a and 74 b of the U-shapedflange 74 each include a respective slot 77 a and 77 b defined thereinwhich are each dimensioned to receive a free end of an elongated drivebar 75. Drive bar 75, in turn, is dimensioned to sit within a drive slot147 which is part of the knife assembly 140 explained in detail below.The trigger assembly 70 is mounted atop the donut-like drive ring 141 ofthe knife assembly 140. Proximal activation of the finger actuator 71rotates the trigger assembly 70 about pivot pin 73 which, in turn,forces the drive bar 75 distally, which, as explained in more detailbelow, ultimately extends the knife 185 through the tissue 420. A spring350 biases the knife assembly 70 in a retracted position such that aftersevering tissue 420 the knife 185 and the knife assembly 70 areautomatically returned to a pre-firing position.

[0119] As mentioned above, the locking flange 44 abuts tabs 76 a and 76b when the handle 40 is disposed in a non-actuated position. When thehandle 40 is actuated and flange 90 is fully reciprocated within channel51 of the fixed handle 50, the locking flange 44 moves proximallyallowing activation of the trigger assembly 70 (See FIGS. 37 and 44).

[0120] Drive assembly 150 includes reciprocating sleeve 60, drivehousing 158, spring 67, drive ring 159, drive stop 155 and guide sleeve157 which all cooperate to form the drive assembly 150. Moreparticularly and as best shown in FIGS. 28 and 29, the reciprocatingsleeve 60 includes a distal end 65 which as mentioned above has anaperture 62 formed therein for actuating the detent 117 of jaw member110. The distal end 65 preferably includes a scoop-like support member69 for supporting the proximal end of the fixed jaw member 120 therein.The proximal end 61 of the reciprocating sleeve 60 includes a slot 68defined therein which is dimensioned to slidingly support the knifeassembly 70 for longitudinal reciprocation thereof to sever tissue 420.The slot 68 also permits retraction of the reciprocating sleeve 60 overthe knife assembly 140 during the closing of jaw member 110 relative tojaw member 120.

[0121] The proximal end 61 of the reciprocating sleeve 60 is positionedwithin an aperture 151 in drive housing 158 to permit selectivereciprocation thereof upon actuation of the movable handle 40. Thespring 67 is assembled atop the drive housing 158 between a rear stop156 of the drive housing 158 and a forward stop 154 of the drive ring159 such that movement of the forward stop 154 compresses the spring 67against the rear stop 156 which, in turn, reciprocates the drive sleeve60. As a result thereof, the jaw members 110 and 120 and the movablehandle 40 are biased by spring 67 in an open configuration. The drivestop 155 is fixedly positioned atop the drive housing 158 and biases theupper flanges 45 a and 45 b of the movable handle 40 when actuated suchthat the driving flange 47 forces the stop 154 of the drive ring 159proximally against the force of the spring 67. The spring 67, in turn,forces the rear stop 156 proximally to reciprocate the sleeve 60 (SeeFIG. 40). Preferably, the rotating assembly 80 is located proximate thedriving flange 47 to facilitate rotation of the end effector assembly100. The guide sleeve 157 mates with the proximal end 61 of thereciprocating sleeve 60 and affixes to the drive housing 158. Theassembled drive assembly 150 is shown best in FIG. 20.

[0122] As best shown in FIGS. 18 and 21-24, the knife assembly 140includes an elongated rod 182 having a bifurcated distal end comprisingprongs 182 a and 182 b which cooperate to receive a knife bar 184therein. The knife assembly 180 also includes a proximal end 183 whichis keyed to facilitate insertion into tube 160 of the rotating assembly80. A knife wheel 148 is secured to the knife bar 182 by a pin 143. Moreparticularly, the elongated knife rod 182 includes apertures 181 a and181 b which are dimensioned to receive and secure the knife wheel 148 tothe knife rod 182 such that longitudinal reciprocation of the knifewheel 148, in turn, moves the elongated knife rod 182 to sever tissue420.

[0123] The knife wheel 148 is preferably donut-like and includes rings141 a and 141 b which define a drive slot 147 designed to receive thedrive bar 75 of the trigger assembly 70 such that proximal actuation ofthe trigger assembly 70 forces the drive bar 75 and the knife wheel 148distally. It is envisioned that aperture 181 a may be used for aparticular trigger assembly 70 configuration and aperture 181 b may beused for a different trigger assembly 70 configuration. As such, pin 143is designed for attachment through either aperture 181 a or 181 b tomount the knife wheel 148 (See FIG. 24). Knife wheel 148 also includes aseries of radial flanges 142 a and 142 b which are dimensioned to slidealong both channel 163 of tube 160 and slot 68 of the reciprocatingsleeve 60 (See FIG. 15).

[0124] As mentioned above, the knife rod 182 is dimensioned to mount theknife bar 184 between prongs 182 a and 182 b preferably in friction-fitengagement. The knife bar 184 includes a series of steps 186 a, 186 band 186 c which reduce the profile of the knife bar 184 towards thedistal end thereof. The distal end of the knife bar 184 includes a knifesupport 188 which is dimensioned to retain knife blade 185. The end ofthe knife support preferably includes a chamfered edge 188 a. It isenvisioned that the knife blade 185 may be welded to the knife support188 of secured in any manner known in the trade.

[0125] As best shown in the exploded view of the FIGS. 14 and 30-32, theelectrical leads 310 a, 310 b, 310 c and 311 are fed through the housing20 by electrosurgical cable 310. More particularly, the electrosurgicalcable 310 is fed into the bottom of the housing 20 through fixed handle50. Lead 310 c extends directly from cable 310 into the rotatingassembly 80 and connects (via a fused clip or spring clip or the like)to tube 60 to conduct the second electrical potential to fixed jawmember 120. Leads 310 a and 310 b extend from cable 310 and connect tothe hand switch or joy-stick-like toggle switch 200.

[0126] Switch 200 includes an ergonomically dimensioned toggle plate 205having a pair of wings 207 a and 207 b which preferably conform to theouter shape of housing 20 (once assembled). It is envisioned that theswitch 200 permits the user to selectively activate the forceps 10 in avariety of different orientations, i.e., multi-oriented activation. Ascan be appreciated, this simplifies activation. A pair of prongs 204 aand 204 b extend distally and mate with a corresponding pair ofmechanical interfaces 21 a and 21 b disposed within housing 20 (See FIG.32). Prongs 204 a and 204 b preferably snap-fit to the housing 20 duringassembly. Toggle plate 205 also includes a switch interface 203 withmates with a switch button 202 which, in turn, connects to electricalinterface 201. The electrical leads 310 a and 310 b are electricallyconnected to electrical interface 201. When the toggle plate 205 isdepressed, trigger lead 311 carries the first electrical potential tojaw member 110. More particularly, lead 311 extends from interface 201through a plurality of slots 84 a, 84 b and 84 c of the rotatingassembly 80 (See FIGS. 25 and 30) and along the upper portion of tube160 and eventually connects to the movable jaw member 110 as describedabove (See FIGS. 32, 34 and 35).

[0127] When the switch 200 is depressed, electrosurgical energy istransferred through leads 311 and 310 c to jaw members 110 and 120,respectively. It is envisioned that a safety switch or circuit (notshown) may be employed such that the switch cannot fire unless the jawmembers 110 and 120 are closed and/or unless the jaw members 110 and 120have tissue 420 held therebetween. In the latter instance, a sensor (notshown) may be employed to determine if tissue 420 is held therebetween.In addition, other sensor mechanisms may be employed which determinepre-surgical, concurrent surgical (i.e., during surgery) and/or postsurgical conditions. The sensor mechanisms may also be utilized with aclosed-loop feedback system coupled to the electrosurgical generator toregulate the electrosurgical energy based upon one or more pre-surgical,concurrent surgical or post surgical conditions. Various sensormechanisms and feedback systems are described in commonly-owned,co-pending U.S. patent application Ser. No. 10/427,832 entitled “METHODAND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR” filed on May1, 2003 the entire contents of which are hereby incorporated byreference herein.

[0128] Preferably, the jaw members 110 and 120 are electrically isolatedfrom one another such that electrosurgical energy can be effectivelytransferred through the tissue 420 to form seal 450. For example and asbest illustrated in FIGS. 32, 34 and 35, each jaw member, e.g., 110,includes a uniquely-designed electrosurgical cable path disposedtherethrough which transmits electrosurgical energy to the electricallyconductive sealing surface 112. It is envisioned that jaw member 110 mayinclude one or more cable guides or crimp-like electrical connectors todirect cable lead 311 towards electrically conductive sealing surface112. Preferably, cable lead 311 is held loosely but securely along thecable path to permit rotation of the jaw member 110 about pivot 103. Ascan be appreciated, this isolates electrically conductive sealingsurface 112 from the remaining operative components of the end effectorassembly 100, jaw member 120 and shaft 12. As explained in detail above,the second electrical potential is conducted to jaw member 120 throughtube 160. The two potentials are isolated from one another by virtue ofthe insulative sheathing surrounding cable lead 311.

[0129] It is contemplated that utilizing a cable feed path for cablelead 311 and by utilizing a conductive tube 160 to carry the first andsecond electrical potentials not only electrically isolates each jawmember 110 and 120 but also allows the jaw members 110 and 120 to pivotabout-pivot pin 103 without unduly straining or possibly tangling cablelead 311. Moreover, it is envisioned that the simplicity of theelectrical connections greatly facilitates the manufacturing andassembly process and assures a consistent and tight electricalconnection for the transfer of energy through the tissue 420.

[0130] As mentioned above, it is envisioned that cable leads 311 and 310c are fed through respective halves 82 a and 82 b of the rotatingassembly 80 in such a manner to allow rotation of the shaft 12 (viarotation of the rotating assembly 80) in the clockwise orcounter-clockwise direction without unduly tangling or twisting thecable leads 311 and 310 c. More particularly, each cable lead 311 and310 c is fed through a series of conjoining slots 84 a, 84 b, 84 c and84 d located in the two halves 82 a and 82 b of the rotating assembly80. Preferably each conjoining pair of slots, e.g., 84 a, 84 b and 84 c,84 d, are large enough to permit rotation of the rotating assembly 80without unduly straining or tangling the cable leads 311 and 310 c. Thepresently disclosed cable lead feed path is envisioned to allow rotationof the rotation assembly approximately 180 degrees in either direction.

[0131] Turning back to FIG. 14 which shows the exploded view of thehousing 20, rotating assembly 80, trigger assembly 70, movable handle 40and fixed handle 50, it is envisioned that all of these variouscomponent parts along with the shaft 12 and the end effector assembly100 are assembled during the manufacturing process to form a partiallyand/or fully disposable forceps 10. For example and as mentioned above,the shaft 12 and/or end effector assembly 100 may be disposable and,therefore, selectively/releasably engagable with the housing 20 androtating assembly 80 to form a partially disposable forceps 10 and/orthe entire forceps 10 may be disposable after use.

[0132] As best seen in FIG. 13, once assembled, spring 67 is poised forcompression atop drive housing 158 upon actuation of the movable handle40. More particularly, movement of the handle 40 about pivot pins 29 aand 29 b reciprocates the flange 90 into fixed handle 50 and forcesdrive flange 47 against flange 154 of drive ring 159 to compress spring67 against the rear stop 156 to reciprocate the sleeve 60 (See FIG. 40).

[0133] Preferably, the trigger assembly 70 is initially prevented fromfiring by the locking flange 44 disposed on movable handle 40 whichabuts against the trigger assembly 70 prior to actuation. It isenvisioned that the opposing jaw members 110 and 120 may be rotated andpartially opened and closed without unlocking the trigger assembly 70which, as can be appreciated, allows the user to grip and manipulate thetissue 420 without premature activation of the knife assembly 140. Asmentioned below, only when the t-shaped end 95 of flange 90 iscompletely reciprocated within channel 51 of the fixed handle 50 andseated within pre-defined catch basin 194 will the locking flange allowactivation of the trigger assembly 70. The operating features andrelative movements of these internal working components of the forceps10 are shown by phantom representation and directional arrows and arebest illustrated in FIGS. 36-49.

[0134]FIG. 36 shows the forceps approximating tissue. As the handle 40is squeezed and flange 90 is incorporated into channel 54 of fixedhandle 50, the drive flange 47, through the mechanical advantage of theover the center pivot pins 29 a and 29 b is rotated generally proximallyto compress spring 67. Simultaneously, the reciprocating sleeve 60 ispulled proximally by the movement of rear ring 156 which, in turn,causes aperture 62 of sleeve 60 to proximally cam detent 117 and closethe jaw member 110 relative to jaw member 120 (See FIGS. 37-40).

[0135] It is envisioned that the mechanical advantage of theover-the-center pivot will enable the user to selectively compress thecoil spring 67 a specific distance which, in turn, imparts a specificload on the reciprocating sleeve 60. The reciprocating sleeve's 60 loadis converted to a torque about the jaw pivot 103. As a result, aspecific closure force can be transmitted to the opposing jaw members110 and 120. As mentioned above, the jaw members 110 and 120 may beopened, closed and rotated to manipulate tissue 420 until sealing isdesired without unlocking the trigger assembly 70. This enables the userto position and re-position the forceps 10 prior to activation andsealing. More particularly, as illustrated in FIG. 4, the end effectorassembly 100 is rotatable about longitudinal axis “A” through rotationof the rotating assembly 80.

[0136] Once the desired position for the sealing site is determined andthe jaw members 110 and 120 are properly positioned, handle 40 may becompressed fully such that the t-shaped end 95 of flange 90 clears apredefined rail edge 193 located atop the triangular-shaped members 57.Once end 95 clears edge 193, the end is directed into catch basin 194located within the exit pathway 58. More particularly, upon a slightreduction in the closing pressure of handle 40 against handle 50, thehandle 40 returns slightly distally towards entrance pathway 54 but isre-directed towards exit pathway 58 into catch basin 194 (See FIG. 38).At this point, the release or return pressure between the handles 40 and50 which is attributable and directly proportional to the releasepressure associated with the compression of the drive assembly 150causes the end 95 of flange 90 to settle or lock within catch basin 194.Handle 40 is now secured in position within fixed handle 50 which, inturn, locks the jaw members 110 and 120 in a closed position against thetissue 420.

[0137] At this point the jaws members 110 and 120 are fully compressedabout the tissue 420 (FIG. 26). Moreover, the forceps 10 is now readyfor selective application of electrosurgical energy and subsequentseparation of the tissue 420, i.e., as t-shaped end 95 seats withincatch basin 194, locking flange 44 moves into a position to permitactivation of the trigger assembly 70 (FIGS. 44 and 45).

[0138] As the t-shaped end 95 of flange 90 becomes seated within catchbasin 194, a proportional axial force on the reciprocating sleeve 60 ismaintained which, in turn, maintains a compressive force betweenopposing jaw members 110 and 120 against the tissue 420. It isenvisioned that the end effector assembly 100 and/or the jaw members 110and 120 may be dimensioned to off-load some of the excessive clampingforces to prevent mechanical failure of certain internal operatingelements of the end effector 100.

[0139] As can be appreciated, the combination of the mechanicaladvantage of the over-the-center pivot along with the compressive forceassociated with the compression spring 67 facilitate and assureconsistent, uniform and accurate closure pressure about the tissue 420within the desired working pressure range of about 3 kg/cm² to about 16kg/cm² and, preferably, about 7 kg/cm² to about 13 kg/cm². Bycontrolling the intensity, frequency and duration of the electrosurgicalenergy applied to the tissue 420, the user can either cauterize,coagulate/desiccate, seal and/or simply reduce or slow bleeding. Asmentioned above, two mechanical factors play an important role indetermining the resulting thickness of the sealed tissue andeffectiveness of the seal 450, i.e., the pressure applied betweenopposing jaw members 110 and 120 and the gap distance “G” between theopposing sealing surfaces 112, 122 of the jaw members 110 and 120 duringthe sealing process. However, thickness of the resulting tissue seal 450cannot be adequately controlled by force alone. In other words, too muchforce and the two jaw members 110 and 120 would touch and possibly shortresulting in little energy traveling through the tissue 420 thusresulting in a bad tissue seal 450. Too little force and the seal 450would be too thick.

[0140] Applying the correct force is also important for other reasons:to oppose the walls of the vessel; to reduce the tissue impedance to alow enough value that allows enough current through the tissue 420; andto overcome the forces of expansion during tissue heating in addition tocontributing towards creating the required end tissue thickness which isan indication of a good seal 450.

[0141] Preferably, the electrically conductive sealing surfaces 112, 122of the jaw members 110, 120, respectively, are relatively flat to avoidcurrent concentrations at sharp edges and to avoid arcing between highpoints. In addition and due to the reaction force of the tissue 420 whenengaged, jaw members 110 and 120 are preferably manufactured to resistbending. For example, the jaw members 110 and 120 may be tapered alongthe width thereof which is advantageous for two reasons: 1) the taperwill apply constant pressure for a constant tissue thickness atparallel; 2) the thicker proximal portion of the jaw members 110 and 120will resist bending due to the reaction force of the tissue 420.

[0142] As mentioned above, at least one jaw member, e.g., 120, mayinclude a stop member 750 which limits the movement of the two opposingjaw members 110 and 120 relative to one another. Preferably, the stopmember 750 extends from the sealing surface 122 a predetermined distanceaccording to the specific material properties (e.g., compressivestrength, thermal expansion, etc.) to yield a consistent and accurategap distance “G” during sealing (FIG. 41). Preferably, the gap distancebetween opposing sealing surfaces 112 and 122 during sealing ranges fromabout 0.001 inches to about 0.006 inches and, more preferably, betweenabout 0.002 and about 0.003 inches. Preferably, the non-conductive stopmembers 750 are molded onto the jaw members 110 and 120 (e.g.,overmolding, injection molding, etc.), stamped onto the jaw members 110and 120 or deposited (e.g., deposition) onto the jaw members 110 and120. For example, one technique involves thermally spraying a ceramicmaterial onto the surface of the jaw member 110 and 120 to form the stopmembers 750. Several thermal spraying techniques are contemplated whichinvolve depositing a broad range of heat resistant and insulativematerials on various surfaces to create stop members 750 for controllingthe gap distance between electrically conductive surfaces 112 and 122.

[0143] As energy is being selectively transferred to the end effectorassembly 100, across the jaw members 110 and 120 and through the tissue420, a tissue seal 450 forms isolating two tissue halves 420 a and 420b. At this point and with other known vessel sealing instruments, theuser must remove and replace the forceps 10 with a cutting instrument(not shown) to divide the tissue halves 420 a and 420 b along the tissueseal 450. As can be appreciated, this is both time consuming and tediousand may result in inaccurate tissue division across the tissue seal 450due to misalignment or misplacement of the cutting instrument along theideal tissue cutting plane.

[0144] As explained in detail above, the present disclosure incorporatesknife assembly 140 which, when activated via the trigger assembly 70,progressively and selectively divides the tissue 420 along an idealtissue plane in precise manner to effectively and reliably divide thetissue 420 into two sealed halves 420 a and 420 b (See FIG. 46) with atissue gap 475 therebetween. The knife assembly 140 allows the user toquickly separate the tissue 420 immediately after sealing withoutsubstituting a cutting instrument through a cannula or trocar port. Ascan be appreciated, accurate sealing and dividing of tissue 420 isaccomplished with the same forceps 10.

[0145] It is envisioned that knife blade 185 may also be coupled to thesame or an alternative electrosurgical energy source to facilitateseparation of the tissue 420 along the tissue seal 450 (Not shown).Moreover, it is envisioned that the angle of the knife blade tip 185 maybe dimensioned to provide more or less aggressive cutting anglesdepending upon a particular purpose. For example, the knife blade 185may be positioned at an angle which reduces “tissue wisps” associatedwith cutting. More over, the knife blade 185 may be designed havingdifferent blade geometries such as serrated, notched, perforated,hollow, concave, convex etc. depending upon a particular purpose or toachieve a particular result.

[0146] Once the tissue 420 is divided into tissue halves 420 a and 420b, the jaw members 110 and 120 may be opened by re-grasping the handle40 as explained below. It is envisioned that the knife assembly 140generally cuts in a progressive, unidirectional fashion (i.e.,distally).

[0147] As best shown in FIGS. 47-49, re-initiation or re-grasping of thehandle 40 again moves t-shaped end 95 of flange 90 generally proximallyalong exit pathway 58 until end 95 clears a lip 196 disposed atoptriangular-shaped members 57 along exit pathway 58. Once lip 196 issufficiently cleared, handle 40 and flange 90 are fully and freelyreleasable from handle 50 along exit pathway 58 upon the reduction ofgrasping/gripping pressure which, in turn, returns the jaw members 110and 120 to the open, pre-activated position.

[0148] From the foregoing and with reference to the various figuredrawings, those skilled in the art will appreciate that certainmodifications can also be made to the present disclosure withoutdeparting from the scope of the same. For example, it may be preferableto add other features to the forceps 10, e.g., an articulating assemblyto axially displace the end effector assembly 100 relative to theelongated shaft 12.

[0149] It is also contemplated that the forceps 10 (and/or theelectrosurgical generator used in connection with the forceps 10) mayinclude a sensor or feedback mechanism (not shown) which automaticallyselects the appropriate amount of electrosurgical energy to effectivelyseal the particularly-sized tissue grasped between the jaw members 110and 120. The sensor or feedback mechanism may also measure the impedanceacross the tissue during sealing and provide an indicator (visual and/oraudible) that an effective seal has been created between the jaw members110 and 120. Examples of such sensor systems are described incommonly-owned U.S. patent application Ser. No. 10/427,832 entitled“METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR” filedon May 1, 2003 the entire contents of which are hereby incorporated byreference herein.

[0150] Moreover, it is contemplated that the trigger assembly 70 mayinclude other types of recoil mechanism which are designed to accomplishthe same purpose, e.g., gas-actuated recoil, electrically-actuatedrecoil (i.e., solenoid), etc. It is also envisioned that the forceps 10may be used to cut tissue 420 without sealing. Alternatively, the knifeassembly 70 may be coupled to the same or alternate electrosurgicalenergy source to facilitate cutting of the tissue 420.

[0151] Although the figures depict the forceps 10 manipulating anisolated vessel 420, it is contemplated that the forceps 10 may be usedwith non-isolated vessels as well. Other cutting mechanisms are alsocontemplated to cut tissue 420 along the ideal tissue plane.

[0152] It is envisioned that the outer surface of the end effectorassembly 100 may include a nickel-based material, coating, stamping,metal injection molding which is designed to reduce adhesion between thejaw members 110 and 120 with the surrounding tissue during activationand sealing. Moreover, it is also contemplated that the conductivesurfaces 112 and 122 of the jaw members 110 and 120 may be manufacturedfrom one (or a combination of one or more) of the following materials:nickel-chrome, chromium nitride, MedCoat 2000 manufactured by TheElectrolizing Corporation of OHIO, inconel 600 and tin-nickel. Thetissue conductive surfaces 112 and 122 may also be coated with one ormore of the above materials to achieve the same result, i.e., a“non-stick surface”. As can be appreciated, reducing the amount that thetissue “sticks” during sealing improves the overall efficacy of theinstrument.

[0153] One particular class of materials disclosed herein hasdemonstrated superior non-stick properties and, in some instances,superior seal quality. For example, nitride coatings which include, butnot are not limited to: TiN, ZrN, TiAlN, and CrN are preferred materialsused for non-stick purposes. CrN has been found to be particularlyuseful for non-stick purposes due to its overall surface properties andoptimal performance. Other classes of materials have also been found toreducing overall sticking. For example, high nickel/chrome alloys with aNi/Cr ratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 112 and 122 made from or coated with Ni200, Ni201(˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

[0154] As can be appreciated, locating the switch 200 on the forceps 10has many advantages. For example, the switch 200 reduces the amount ofelectrical cable in the operating room and eliminates the possibility ofactivating the wrong instrument during a surgical procedure due to“line-of-sight” activation. Moreover, decommissioning the switch 200when the trigger is actuated eliminates unintentionally activating thedevice during the cutting process. It is also envisioned that the switch200 may be disposed on another part of the forceps 10, e.g., the fixedhandle 40, rotating assembly 80, housing 20, etc.

[0155] While several embodiments of the disclosure have been shown inthe drawings, it is not intended that the disclosure be limited thereto,as it is intended that the disclosure be as broad in scope as the artwill allow and that the specification be read likewise. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

What is claimed is:
 1. An endoscopic bipolar forceps, comprising: ahousing; a shaft affixed to said housing having a movable jaw member anda fixed jaw member at a distal end thereof, said shaft defining alongitudinal axis defined therethrough; a drive assembly for moving saidmovable jaw member relative to the fixed jaw member from a firstposition wherein the movable jaw member is disposed in spaced relationrelative to the fixed jaw member to a second position wherein themovable jaw member is closer to the fixed jaw member for manipulatingtissue; a movable handle being rotatable about a pivot to force a driveflange of said movable handle into mechanical cooperation with saiddrive assembly to move said jaw members from the open and closedpositions, said pivot being located a fixed distance from saidlongitudinal axis and said drive flange being located generally alongsaid longitudinal axis; and a source of electrosurgical energy connectedto each jaw member such that the jaw members are capable of conductingenergy through tissue held therebetween to effect a tissue seal.
 2. Anendoscopic bipolar forceps according to claim 1 further comprising aselectively advanceable knife assembly for cutting tissue in a forwarddirection along the tissue seal.
 3. An endoscopic bipolar forcepsaccording to any preceding claim further comprising a rotating assemblyfor rotating said jaw members about the longitudinal axis definedthrough said shaft.
 4. An endoscopic bipolar forceps according to anypreceding claim further comprising a hand switch disposed within saidhousing and in electromechanical cooperation with said source ofelectrosurgical energy, said hand switch allowing a user to selectivelysupply bipolar energy to said jaw members to effect a seal.
 5. Anendoscopic bipolar forceps according to any preceding claim wherein saidmovable jaw member includes a first electrical potential and said fixedjaw member includes a second electrical potential, wherein said secondelectrical potential is conducted to said fixed jaw member by aconductive tube.
 6. An endoscopic bipolar forceps according to anypreceding claim wherein said conductive tube is connected to saidrotating assembly.
 7. An endoscopic bipolar forceps according to anypreceding claim wherein said drive assembly includes a reciprocatingsleeve which, upon activation of said movable handle, translates to movesaid movable jaw member relative to said fixed jaw member.
 8. Anendoscopic bipolar forceps according to any preceding claim wherein saidmovable jaw member includes a detent which extends beyond said fixed jawmember and which is designed for engagement with said reciprocatingsleeve such that upon translation of said reciprocating sleeve, saidmovable jaw member moves relative to said fixed jaw member.
 9. Anendoscopic bipolar forceps according to any preceding claim wherein saiddrive assembly includes at least one spring.
 10. An endoscopic bipolarforceps according to any preceding claim wherein at least one of saidjaw members includes a series of stop members disposed thereon forregulating the distance between said jaw members during sealing.
 11. Anendoscopic bipolar forceps, comprising: a shaft having a movable jawmember and a fixed jaw member at a distal end thereof; a drive assemblyfor moving said movable jaw member relative to the fixed jaw member froma first position wherein the movable jaw member is disposed in spacedrelation relative to the fixed jaw member to a second position whereinthe movable jaw member is closer to the fixed jaw member formanipulating tissue; a movable handle for actuating said drive assemblyto move said movable jaw member; a source of electrical energy connectedto each jaw member such that the jaw members are capable of conductingenergy through tissue held therebetween to effect a tissue seal; aselectively advanceable knife assembly for cutting tissue in a forwarddirection along the tissue seal; and a rotating assembly for selectivelyrotating said jaw members about said longitudinal axis, said rotatingassembly being located proximate to said movable handle.
 12. Anendoscopic bipolar forceps, comprising: a shaft having a movable jawmember and a fixed jaw member at a distal end thereof; a drive assemblyfor moving said movable jaw member relative to the fixed jaw member froma first position wherein the movable jaw member is disposed in spacedrelation relative to the fixed jaw member to a second position whereinthe movable jaw member is closer to the fixed jaw member formanipulating tissue; a movable handle for actuating said drive assemblyto move said movable jaw member; a source of electrical energy connectedto each jaw member such that the jaw members are capable of conductingenergy through tissue held therebetween to effect a tissue seal; aselectively advanceable knife assembly for cutting tissue in a forwarddirection along the tissue seal; and a stop member disposed on at leastone of said jaw members for regulating the distance between jaw membersduring sealing.
 13. A bipolar forceps according to claim 12 furthercomprising a rotating assembly for rotating said jaw members about alongitudinal axis defined through said shaft.